Combination oxygen tent and nebulizer



Jan. 29, 1963 F. J. EICHELMAN 3,075,523

COMBINATION OXYGEN TENT AND NEBULIZER Filed Sept. 8, 1955 5 Sheets-Sheet1 Q g ((5 8 N I 0 IO 2 o w L m 2 Y .35 K8 "N 8 5 a a? b ,w'l'x/u/xv w nog Q FTP T w r 2 W p on Q N W% 1- v A l 8 z o :0 Q: N m

n no u m N N N S INVENTOR. FRANCIS J. EICHELMAN m BY '8 8' A TORNEY Jan.29, 1963 F. J. EICHELMAN 3,075,523

' COMBINATION OXYGEN TENT AND NEBULIZER Filed Sept. 8, 1955 3Sheets-Sheet 2 ATTORNEY Jan. 29, 1963 F. J. EICHELMAN COMBINATION OXYGENTENT AND NEBULIZER 3 Sheets-Sheet 3 Filed Sept. 8, 1955 o: h I Q. 3 m:Db NF 2.\ w w% 21 z.

INVEN TOR. FRANCIS J. EICHELMAN 7 ATTORNEY ite This invention relates ingeneral to the field of inhalation therapy and more particularly to theadministration of oxygen by means of an oxygen tent and associatedcanopy for confining the special atmosphere thus provided at the pointof its use. Specifically, this invention is concerned with thecombination of a nebulizer and an oxygen tent, whereby a high volume ofliquid is entrained in a gaseous stream of oxygen and cooled in the tentapparatus prior to its delivery into an associated canopy.

Inhalation therapy involving the administration of oxygen to a patientby means of a canopy to confine the gas and an associated tent forpreparing the oxygen-enriched atmosphere to be delivered into the canopyis well known. For a more complete treatment of this particular subject,reference may be had to Effective Inhalation Therapy and particularlychapter 23, by Doctors E. R. Levine, A. L. Barach, I. W. Peabody and M.S. Segal, published by National Cylinder Gas Company, Chicago, Illinois,1953. In general, the oxygen tent is the apparatus through which theoxygen is circulated prior to its injection or entry into the associatedcanopy. Conventional oxygen tents are primarily of two types, the icecooled type and the iceless type.

In the former, as the name implies, the tent apparatus is essentially achest or insulated cooling chamber for containing a quantity of crackedice. Oxygen is passed into such a cooling chamber and through or overthe ice in an elfort to cool the oxygen, in order to control somewhatthe temperature within the canopy.

' The other general type of oxygen tent is known as an iceless tent,since it is provided with mechanical refrigerating apparatus of wellknown type, generally involving compressor, coils, condenser,refrigerant media, and a prime mover. Since it is preferable that oxygentents be mobile, the prime mover in an iceless tent is generally anelectric motor. In this type of tent it is apparent that there is noinherent means available for humidifying the oxygen, and it has beencustomary in the past to bubble the supply of oxygen through water priorto its entrance into the tent to humidify the atmosphere in the canopy.In this latter procedure considerable disadvantages are encountered.First, it is a fact that in a bubble type of humidifier wherein theoxygen is merely bubbled through a liquid, regardless of any control ofthe rate of flow of the gas, there can not be provided suflicientmoisture to be of substantial therapeutic value. Second, the use of resPatent a conventional humidifier, even of the nebulizer type,

within the canopy itself, is disadvantageous because most such availablehumidifiers have rather small throughput capacities, and are designedprimarily for use in connection with small enclosures for localinhalation therapy, such as masks and the like. Moreover, it isimpossible with such an arrangement to obtain proper recirculation, sothat in general, although temperature within the canopy itself can becontrolled by means of the refrigerating apparatus in the tent, highhumidities or atmospheres with high liquid content within the canopy cannot be achieved, or it achieved at all, the moitsure is provided in suchlarge particle sizes that it precipitates rapidly within the canopy.

Applicant has overcome all of the foregoing disadvantages by theprovision of an improved high volume nebulizer in combination with thetent cooling apparatus itself, whereby in a single unit there isprovided a simple and positive control of the temperature as well ascontrol of liquid entrainment or humidifying operations andrecirculation. All of this takes place outside of the canopy and therebyachieves a superior therapy control arrangement without interfering withthe comfort or other treatment of the patient. Moreover, applicant hasachieved, by combining the high volume nebulizer with the tent coolingapparatus itself, volume liquid entrainment and higher humidityconditions within tent canopies heretofore thought impossible withoutdetracting from close temperature control within the canopy itself.

It is accordingly the principal object of this invention to provide incombination, improved apparatus for maintaining highly efficienttemperature and canopy atmosphere control.

Another object of this invention is to provide a highly efiicient highvolume nebulizer in combination with an oxygen tent of either theiceless or ice cooled variety.

It is a further object in conjunction with the immediately foregoingobject, to provide an oxygen tent capable of recirculating andrehumidifying the recirculated atmosphere incoming from the tent canopyto thereby achieve maximum humidity within the tent canopy whilemaintaining optimum temperature conditions therein and withoutinterfering with or inconveniencing the patient or affecting othertreatment desired within the canopy itself.

These objects and additional advantages and features of applicantsinvention will become more readily apparent as the following descriptionproceeds, taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a side elevation of the tent apparatus in combination with thehigh volume nebulizer and associated apparatus for suspending a tentcanopy.

FIG. 2 is a cross-sectional view on line 2-2 of FIG. 1.

FIG. 3 is a top plan view of the tent combination with the high volumenebulizer, and particularly illustrating the manner in which thesuspension means for suspending the canopy is adjus-tably associatedwith the tent itself; and

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 3,illustrating the construction of the new high volume nebulizer per se.

Referring now more particularly to FIG. 1 of the drawings, numeral 10represents an oxygen tent. As is somewhat conventional in oxygen tents,particularly of the ice cooled variety, which is portable and suspendedfrom the head of a hospital type bed, the tent generally is rectangularin shape and is provided with double side and bottom walls 11, 12 and13, between which a suitable insulating material 14 such as fiberglassor the like is placed. The walls and bottom of the chest may, of course,be made of any appropriate material. In the preferred embodimentillustrated, this material is a high alloy sheet steel of the stainlessvariety. A closure member 15 is provided which, like the walls 11 and12, is preferably of dual wall construction and provided with anintermediate layer of insulating material (not shown) similar to thatbetween walls 11. and 12. The cover 15 is provided on each side withsuitable securing devices such as toggle clasps 16 which engage lugs 17provided for that purpose on the exterior side walls. Preferably on thesame side walls that support the lugs 17 and somewhat below, there areprovided carrying handles 18.

The side of the tent adapted to face the bed is provided with a pair oftubular members 20 (FIG. 3) projecting centrally thereof, and, from theends of these tubular members 20 extend upwardly individual canopysupporting rods 21 (FIG. 1). These rods 21 extend upwardly preferablyabove the top of the tent 10 from about 2 to 4 feet whereat they arebent outwardly as at 22 and then again at right angles to extendgenerally horizontally at 23, preferably over the edges of a standardhospital size bed. The forwardly extending horizontal members 23 areeach provided with a slide ferrule and binge arrangement 24 fordetachment or folding of the canopy supporting members when not in use,and telescoping extensions 25 for adjusting the longitudinal extent ofthe canopy suspension to accommodate the particular size of canopyprescribed. To maintain a certain amount of rigidity in the canopysupporting structure, a forward cross rod 27 is provided which isinsertable into appropriate bores in knurled knobs 26 at the outer endsof the telescoping extensions 25. The canopy itself, indicated inreduced size at 2% in FIG. 1 is generally a transparent plasticenclosure suspended from the supporting structure by suitable straps orrings such as 29 and at its base tucked under the mattress of the bed.

Adjacent the upstanding portions 21 of the tubular members forming thecanopy support, a pair of hooklike members 30 may be provided so thatthe entire tent including the canopy supporting arrangement may besuspended at the rear of the head of a conventional hos pital type bedby hooking the members 30 over the top rail. To maintain the tentupright when suspended from the bed rail as discussed above, and so thatthe canopy support is properly arranged, a bumper member in the form ofa tube 31 is secured to the lower end of the tent and maintains it inspaced relationship and up right position with respect to the head ofthe bed from which it is suspended.

The inside of the tent 10 is provided with a vertical Wall 35 which doesnot extend the full depth of the enclosure but terminates a suitabledistance above the bottom 13, the purpose of which will be describedlater. The partition 36 generally divides the interior of the tent intotwo compartments, one about half as large as the other. The largercompartment 35 is adapted to hold a supply of ice and this isaccomplished by means of erforate ice supporting drain plates 37supported by suitable depending supports or legs 38 at about the levelof the bottom of the partition wall 36. The bottom of the tent chest isprovided with a suitable drain valve 39 from which ice water may bewithdrawn as necessary.

Immediately above the ice supporting plates 37 and arranged about thelower portion at least of the walls of the ice containing compartment35, is provided a continuous tubular coil li), terminating at one end ina con duit 41 and at the other end in a conduit 42. These conduitsextend under the partition 36 and into the smaller chamber 45.

Mounted in the side wall 11 of the tent 10 is the main oxygen supplyinlet 4-6 provided with a threaded fitting to which may be secured aconduit such as a hose from any suitable gas supply such as for exampleone or more manifolded cylinders or from a piped gas supply system. Theoxygen inlet 46 terminates interior of the wall 11 in an elbow 47 (FIG.3). A short length of conduit 48 extends from the elbow 47 into a valveblock 49, forming part of a two-way valve 59 also attached to the wall11 and situated adjacent the oxygen inlet 46. From the block 49 of thetwo-way valve 56, a conduit 51 (FIG. 2) extends directly to a header 52supplying the nebulizer 69 to be described later. The conduit 42 formingone end of the coil 46 is also connected to the block 49 of the two-wayvalve 50, and the other end 41 of the coil 46 is connected to thenebulizer header 52. The tent it? is further provided with an additionaloxygen inlet 54, preferably capped or valved, conveniently shownprovided with a barbed end (FIG. 1) to which another supply conduit suchas a hose may be readily secured.

The two-way valve 56 is manually operable to two positions and isarranged so that in one position oxygen entering the inlet 45 is passedfrom one outlet of the valve directly through the conduit 51 to thenebulizer header 52. In the other position of the valve 50, the

oxygen entering the inlet 46 is not permitted to pass directly to thenebulizer through conduit 51, but is passed from another outlet of thevalve through the conduit 42 and coil 49 in heat exchange relationshipwith the cooling media, and then through the conduit 41 to the nebulizer69 by way of the nebulizer header 52. In this way, should thetemperature in the canopy fall below the desired temperature, the valvemay be manipulated so that uncooled oxygen is passed into the canopyuntil the temperature has been properly adjusted.

In certain instances, where more than a momentary or short-termadjustment is necessary to maintain a desired temperature or humidity inthe canopy, the twoway valve may be manipulated so that the oxygenentering the inlet 46 is passed through the coil 46 to the nebulizer,and a how meter (not shown) upstream of the inlet d6 is adjusted topermit only a portion if the amount of oxygen required for the patientto flow into the inlet 46. Another oxygen conduit is then attached fromthe supply to the second or additional valved oxygen inlet 54, andanother flow meter (not shown) upstream of this inlet 54 is adjusted toprovide the re mainder of the required oxygen flow uncooled directlyinto the tent 1t) and through a venturi of the nebulizer 60, asdescribed below in connection with the function of the nebulizer andtent combination. In this manner, it will be seen that, should somefairly substantial temperature unbalance be noted in the canopy, it canbe stabilized quickly by manipulation of the two-way valve 50 andthereafter the stabilized temperature may be maintained by utilizing acombination of uncooled gas entering through the oxygen inlet 54, mixedwith cooled oxygen having been passed through the coil 44 the relativeamounts of oxygen passing through the inlets 46 and 54 being regulatedby flow meters (not shown) upstream of these connections. Such flowmeters are readily available and are standard equipment in anyinstallation requiring or utilizing an oxygen tent, and are consideredconventional, necessary auxiliary equipment. It will also be noted thatthe amount of liquid nebulized and introduced into the canopy may alsobe varied.

The nebulizer apparatus 60 comprises a block-like housing 61 which issecured to a wall 62 of the tent chest 10 by suitable means such as abracket and bolts 63. In the apparatus illustrated the nebulizerassembly 61 is preferably secured to the other side of the wall 62 ofthe tent 10 between the wall and the tent supporting structure 21, inwhich position it is readily accessible to an attendant for cleaning andreplenishing of the liquid supply and yet is in a position where it issubstantially protected from damage by virtue of the adjacent members 2t21, 22 and 31 of the canopy supporting structure. The block-likenebulizer housing at is preferably of a clear plastic material and isprovided with a central bore 65 flaring outwardly in an intermediatesection at 66, to a larger diameter bore e7 at an opposite endconcentric with the bore 65. The bore 65 is provided with a tubularmember 7i? which is press fit into the bore 65 and extends rearwardlytherefrom. The tubular member 70 may be of any material and ispreferably of a substantially non-corrosive metal, and forms anauxiliary housing for the nebulizer gas and liquid jets to be describedlater. Within the larger size bore 67 at the outwardly flared end of theintermediate bore 66 are positioned a series of mesh screening members68, preferably of woven stainless steel wire or rod. In the apparatusillustrated there are four such pieces of mesh 68, which are placed withrespect to one another at random so that the openings defined by themesh are not in register. The purpose for this screening mesh will bedescribed later in conjunction with the operation of the nebulizer.

The forward or delivery end of the housing 61 is completed by anotherblock 71, preferably of the same material as 61, which is centrallybored at 72 and then flared outwardly at 7?: to its greatest diameter,which is substantially the same as the diameter of the bore of 67 whichholds the wire mesh 63 in the block 61. Together the flared walls 66 and73 form a venturi chamber centrally and transversely of which thescreening 63 is located. From the forward end of the bore 72, thereextends a tubular member 75, the purpose for which is to project throughan opening (not shown) for that purpose in an associated canopy 28. Theforward assembly '71 is secured to the nebulizer main housing 61 bymeans of a plate 76, preferably of metal, and screws 77 in the mannerbest illustrated in FIG. 4, thereby completing the nebulizer housing.

Beneath and suspended from the nebulizer housing 61 is a receptacle 81)adapted to contain the liquid to be nebulized. The receptacle 30 may beformed of any suitable material, but preferably is of .a translucentplastic material for resistance to breakage in handling and to renderits interior readily visible. The receptacle 80 is preferably providedat its upper end with a peripheral groove 81 for engagement by one ormore oppositely spaced inturned clamps 82, adjustably secured to theblock 61 by a threaded hand wheel arrangement 83, one of which isillustrated in FIG. 1. The receptacle may be easily removed and replacedby manipulation of either of these clamps.

Extending from the tubular housing 70 within the block 61 and downwardlyinto the receptacle 80 is a tubular withdrawal conduit 84, at its lowerend provided with a plurality of intake ports 85 and screening material86, to prevent the ingress of sediment or other solids which may collectat the bottom of the receptacle. The upper end of the tubular member 84terminates in a liquid jet 90 having an orifice 91 and mounted on abracket 95, which is secured by any suitable means such as by brazing tothe tubular housing 70. One end 96 of the bracket 95 is provided with aguide opening, through which a gas nozzle 18%) extends, provided with arestricted orifice 161. The gas nozzle 100 is maintained in place bymeans of another bracket 105, which is secured to the inside of the wall62 of the tent chest by means of screws or bolts, such as 10 Theposition of this bracket and the bolts is more clearly illustrated inFIG. 2. The rear end of the gas nozzle 1% is connected by a threadedcoupling 182 to the nebulizer header 52, as best illustrated in FIG. 4.

At the forward end of the bracket 95 there is positioned a target memberor impingement surface 119, which is secured to the bracket 95 by meansof a leg 111. The preferably spherical target member 110 is positionedwithin the venturi chamber 115 formed by the flaring walls 66 and 73 inthe housing assembly 61 and 71. The bracket 95 maintains the relativepositions of the gas nozzle 1%, the liquid nozzle 9d, and the targetmember 116 in a preadjusted position adapted to secure maximumnebulization of liquid. This is best accomplished by forming andpositioning the bracket 95 so that the gas nozzle 10%) extendssubstantially axially into the tubular housing 7t} to a position inwhich its orifice 1 51 is closely adjacent the orifice 91 of the liquidnozzle 99. The orifice end of the liquid nozzle 90 is preferably taperedtoward the orifice 91 which is preferably positicned in a plane slightlyabove the center of the orifice 161 of the gas nozzle 1%. In thismanner, gas issuing from the gas nozzle 106 will strike first thetapered end of the liquid nozzle 9d, and be deflected upwardly adjacentthe liquid orifice )1 and therefrom against the target 11%, the centerof which is substantially in line with the proiected axis of the gasnozzle 100, but at a greater distance from the liquid nozzle orifice 91than the latter is positioned from the gas nozzle orifice 1&1.

This nebulizer is adapted to nebulize and deliver a high volume ofliquid in minute particle sizes in the range of 3 microns or less. Toinsure that particle sizes delivered through the delivery tube 75 intothe canopy are substantially uniform, the screening 68 is provided sothat larger moisture particles are deposited thereagainst and drainthrough the tube 87 back into receptacle 89 and the liquid supply.

The device is completed with .a transverse bore 119 forming aninspection port preferably in the upper portion of the nebulizer mainhousing 61 and the tubular chamber 7b in the vicinity of the liquid andgas nozzles E i? and 105, and is provided with a suitable closure member12%. In this manner the operating apparatus may be inspected by removalof the closure 120, and particularly if for any reason the liquid nozzlebecomes clogged, it is readily accessible and may be cleaned byinserting a fine wire through the inspection port 119 into the liquidorifice 91.

It will be noted that the rear of the housing 70 opens into the tentchamber 45. In the other or ice containing chamber 36 of the tent 10there is another port 124, forwardly of which extends a second tube 125which projects into the canopy 28. It will be noted that the venturichamber of the nebulizer creates an area of low pressure rearwardthereof within the housing 70 so that moisture laden gas entering thecanopy through the delivery tube 75 is recirculated from the canopythrough the return tube into the larger ice chamber 35 of the tent 1! inwhich it will be cooled. As this recirculated atmosphere is cooled bythe ice, a certain amount of moisture and dissolved impurities will becondensed out and washed by the melting ice to the bottom of the tent 16where it and melted ice is withdrawn from time to time through the drainvalve 39. The thus cooled atmosphere is then passed below the partition36 through chamber 45, into the housing 70, and again through thenebulizer by way of the venturi chamber 115. In this manner a constantcirculation, recooling and humidification of the canopy atmosphere isachieved without mechanical means necessitating moving parts. It shouldalso be noted that the venturi arrangement of the nebulizer 60 will drawoxygen admitted directly into the tent by way of the additional oxygeninlet 54, through the nebulizer venturi and into the canopy 28 withoutincreasing the nebulizing rate of the nebulizer. In this manner extraoxygen may be introduced for such purposes as ilushing the tent andcanopy, varying the percentage introduction of liquid into the canopy,varying the volume of recirculated canopy atmosphere, and as referred toearlier, effecting to some degree, temperature control and maintenancewithin the canopy.

it will be seen, therefore, that by combining a high volume nebulizerdirectly with an oxygen tent apparatus, numerous advantages areachieved. In addition to accomplishing recirculation of the atmospherewithin the canopy itself by means requiring no mechanical moving parts,the recirculated atmosphere is simply and efii ciently additionallycooled and fully resaturated as it is repassed through the nebulizerapparatus.

It will be apparent to those skilled in the art that applicantscombination of a high volume nebulizer and an oxygen tent is applicablenot only to an ice cooled type of tent as illustrated in the preferredembodiment herein, but is equally applicable to the so-called icelesstent in which mechanical refrigerating apparatus is substituted for tieice chest refrigeration means presented here. In conventional iceless ormechanically refrigerated tents, it has been heretofore necessary toprovide a mechanical blower apparatus in the form of a fan or squirrelcage type of impeller for moving and recirculating the canopy atmosphereand, as noted hereinbefore in connection with the iceless tent,applicants invention may dispense with this movable mechanicalapparatus. However, in certain installations where it is desired to movehigher volumes of gas, it is entirely feasible that applicantscombination may include, particularly in an iceless type of tent, ablower apparatus. This may be equally true in the ice cooled type oftent where additional higher volumes of circulated atmosphere arerequired. Such requirements are directly dependent upon the size of thecanopy employed, which obviously regulates the control volume of theatmosphere in which the patient is treated.

Likewise, although applicant discloses herein a preferred embodiment ofhigh volume nebulizer, it is obvibus that other high volume nebulizersmay be substituted in applicants combination and function in the samemanner with either the ice cooled or iceless variety of tent apparatus.It will be apparent, therefore, that certain modifications will besuggested to those skilled in the art, and all such modifications .ascome Within the spirit of this invention are intended to be includedWithin its scope, as defined by the appended claims.

ll claim:

'1. In an oxygen tent apparatus for controlled inhalation 'thereapy inassociation with a canopy, the combination comprising a heat insulatedcooling chamber, a tubular coil within said chamber for passage of anoxygen-containing gas in heat exchange relationship with a coolingmedium, a liquid nebulizer adapted to entrain particles -of finelydivided liquid in said oxygen, a gas nozzle for said nebulizer incommunication with the outlet end of said tubular coil, and a by-passconduit in communication with said gas nozzle for shunting uncooledoxygencontaining gas at preselected times directly to the nebulizer.

2. In an oxygen tent apparatus for controlled inhalation therapy inassociation with a canopy, the combination comprising a heat insulatedcooling chamber, a tubular coil within said chamber for passage of anoxygencontaining gas in heat exchange relationship with a coolingmedium, a liquid nebulizer adapted to entrain particles of finelydivided liquid in said oxygen-containing gas, a gas nozzle for saidnebulizer in communication with the outlet end of said tubular coil, atwo-way valve adapted to admit oxygen-containing gas from a sourcethereof, the inlet end of said tubular coil communicating with oneoutlet of said valve, and a bypass conduit communicating the otheroutlet of said valve directly with the nebulizer gas nozzle, said valvebeing operable in one position to pass the oxygen-containing gas throughsaid tubular coil and in the other position to pass uncooledoxygencontaining gas directly to the gas nozzle in the nebulizer.

3. In an oxygen tent apparatus for controlled inhalation therapy inassociation with a canopy, the combination comprising a heat insulatedcooling chamber, a tubular coil within said chamber for passage of anoxygen-containing gas in heat exchange relationship with a coolingmedium, a liquid nebulizer adapted to entrain particles of finelydivided liquid in said oxygen-containing :gas, a gas nozzle for saidnebulizer in communication with the outlet end of said tubular coil, atwo-way valve adapted to admit the oxygen-containing gas from a sourcethereof, the inlet end of said tubular coil communicating with oneoutlet of said valve, and a by-pass conduit com- 'rnunicating the otheroutlet of said valve directly With the nebulizer gas nozzle, said valvebeing operable in one position to pass the oxygen-containing gas throughsaid tubular coil and in the other position to pass uncooledoxygen-containing gas directly to the gas nozzle in the nebulizer,whereby adjustment of temperature in the canopy may be obtained, andanother inlet for entry of substantially uncooled oxygencontaining gasfrom a source thereof in communication with said nebulizer, by means ofwhich in conjunction with manipulation of the two-way valve to passoxygen-containing gas through the tubular coil, the adjusted temperatureor" the canopy atmosphere may he maintained and the oxy en concentrationand liquid content in the canopy may be varied.

4. In an oxygen tent apparatus for controlled inhalation therapy inassociation with a canopy, the combinaiz p l l p plii g a insulatedcooling chamber, a tubular coil within said chamber for passage of anoxygencontaining gas in heat exchange relationship with a cool ingmedium, a liquid nebulizer adapted to entrain particles of finelydivided liquid in said oxygen-containing gas, a gas nozzle for saidnebulizer in communication with the outlet end of said tubular coil, atwo-Way valv adapted to admit oxygen-containing gas from a sourcethereof, the inlet end of said tubular coil communicating with oneoutlet of said valve, and a lay-pass conduit communicating the otheroutlet of said valve directly With the nebulizer gas nozzle, said valvebeing operable in one position to pass oxygen-containing gas throughsaid tubular coil and in the other position to pass uncooled oxygen-comraining gas directly to the gas nozzle in th nebulizer, wherebyadjustment of temperature in the canopy may be obtained, and anotherinlet for entry of substantially uncooled oxygen-containing gas from asource thereof in communication with said nebulizer, by means of whichin conjunction with manipulation of the two-Way valve to passoxygen-containing gas through the tubular coil, the adjusted temperatureof the canopy atmosphere may be maintained, means including a venturichamber communicating the interior of the canopy with the coolingchamber through said nebulizer, and anothe means spaced from said lastmentioned means also communicating the interior of the canopy with thecooling chamber whereby recirculation of the canopy atmosphere throughthe cooling chamber and nebulizer is achieved and the oxygenconcentration and liquid content of the canopy atmosphere varied.

5. An oxygen tent apparatus comprising in combination, an insulatedcooling chamber, a canopy supporting structure secured to one side ofthe cooling chamber, a pair of hook-lik members attached to the base ofsaid canopy supporting structure for suspending the tent from a bedrail, a bumper element secured to the same side of said chamber andbelow the base of the canopy supporting structure to space the tent fromthe bed and maintain it upright, a liquid nebulizer provided with a gasnozzle and a venturi secured to said chamber and Within the spacedefined by the base of the canopy supporting structure and said bumper,said venturi being in communication with the interior of the coolingchamber and the space beneath the canopy supporting structure, anotherconduit spaced from said nebulizer also communicating the interior ofthe cooling chamber and the space within the canopy supportingstructure, a tubular coil Within said cooling chamber the outlet ofwhich is in communication with the neb'ulizer gas nozzle, and means forcommunicating the inlet of said tubular coil with a source of uncoolcdoxygen-containing 6. An oxygen tent apparatus as claimed in claim 5,including valve means operative in one position to pass theoxygen-containing gas through said tubular coil to the nebulizer and inanother position to pass uncooled oxygencontaining gas directly to thenebulizer, and another inlet for direct entry of substantially uncoolcdoxygen-containing gas into the nebulizer venturi independent of saidvalve means Where, by selective use the temperature or" the canopyatmosphere may be regulated and maintained and the liquid content of thecanopy atmosphere varied.

7. An oxygen tent apparatus as claimed in claim 6, in which saidinsulated cooling chamber is adapted to contain a supply of ice.

8. Apparatus for controlled inhalation therapy administcred Within acanopy for confining a special atmosphere at the point of its use,comprising in combination a canopy, a tent external of the canopydivided into two communicating chambers, a tubular coil disposed in oneof said chambers for the passage of a gaseous stream in heat exchangerelationship with a cooling medium, means communicating said one chamberwith said canopy, and a liquid nebulizer adapted to entrain particles offinely divided li uid in said gaseous stream in communication with theother of said chambers, said nebulizer being provided with a gas nozzlein communication with the outlet end of said tubular coil and with aventuri chamber communicating said other of said chambers and saidcanopy.

9. Apparatus as claimed in claim 8, in which the chamber containing thetubular coil is adapted to contain a supply of ice.

10. A nebulizer for entraining minute particles of liquid in a gaseoussteam, comprising a main housing provided with a central longitudinalbore, said bore being flared at an intermediate portion to provide aventuri chamber, a gas nozzle, a liquid nozzle and an impacting surfacespaced apart and positioned substantially at the inlet side of theventuri chamber, and metal Wire mesh screening material positionedcentrally within and transversely of the venturi chamber, said apparatusadapted to pass a stream of gas under pressure from the gas nozzle toadjacent the liquid nozzle to draw liquid therethrough into the streamand impact it into particles against the impacting surface andthereafter to deposit only the largor liquid particles on the meshscreening so that a substantially uniform moisture laden cloud issuesfrom the outlet end of said venturi chamber.

11. A nebulizer for entraining minute particles of liquid in a gaseousstream, comprising a main housing provided with a central longitudinalbore, said bore being flared at an intermediate portion to provide aventuri chamber, a gas nozzle, a liquid nozzle and an impacting surfacespaced apart and positioned substantially at the inlet side of theventuri chamber, and a plurality of nonregistering metal Wire meshscreens positioned Within the venturi chamber in the area of its maximumexpansion and transversely of the venturi chamber, said apparatusadapted to pass a stream of gas under pressure from the gas nozzle toadjacent the liquid nozzle to draw liquid therethrough into the streamand impact it into particles against the impacting surface andthereafter to deposit only the larger liquid particles on the meshscreening so that a substantially uniform moisture laden cloud issuesfrom the outlet end of said venturi chamber.

12. A nebulizer as claimed in claim 11, including an auxiliary tubularhousing extending from the inlet end of said longitudinal bore, said gasnozzle, liquid nozzle and impacting surface being spaced apartsubstantially within and axially of said tubular housing.

13. A nebulizer as claimed in claim 11, including a receptacle adaptedto contain liquid to be nebulized suspended below said main housing, atube extending from said liquid nozzle to adjacent the bottom of saidrecep tacle, and means for draining liquid deposited on said screeningmaterial into the receptacle.

14. A nebulizer for entraining minute particles of liquid in a gaseousstream, comprising a main housing provided with a central longitudinalbore, said bore being flared at an intermediate portion to provide aventuri chamber, a receptacle adapted to contain liquid to be nebulizedsuspended below said main housing, said receptacle being provided with agroove, at least one releasable clamp secured to said main housing andadapted to engage said groove to secure the receptacle in place beneaththe housing, a gas nozzle, a liquid nozzle, a tube extending from saidliquid nozzle to adjacent the bottom of said receptacle, an impactingsurface spaced apart and positioned substantially at the inlet side ofsaid venturi chamber, a plurality of non-registering mesh screenspositioned within the venturi chamber in the area of its maximumexpansion and transversely of the venturi chamber, said apparatusadapted to pass a stream of gas under pressure from the gas nozzle toadjacent the liquid nozzle to draw liquid therethrough into the streamand impact it into particles against the impacting surface andthereafter to deposit only the larger liquid particles on the meshscreening so that a substantially uniform moisture laden cloud issuesfrom the outlet end of said venturi chamber, and means for drainingliquid deposited on said screen material into the receptacle.

15. A nebulizer for entraining minute particles of liquid in a gaseousstream, comprising a main housing provided with a central longitudinalbore, said bore being flared at an intermediate portion to provide aventuri chamber, a gas nozzle, a liquid nozzle, an inspection port insaid main housing adjacent the gas and liquid nozzles and a closure forsaid port, an impacting surface spaced apart and positionedsubstantially at the inlet side of the venturi chamber, and a pluralityof non-registering mesh screens positioned in the venturi chamber in thearea of its maximum expansion and transversely of the venturi chamber,said apparatus adapted to pass a stream of gas under pressure from thegas nozzle to adjacent the liquid nozzle to draw liquid therethroughinto the stream and impact it into particles against the impactingsurface and thereafter to deposit only the larger liquid particles onthe mesh screening so that a substantially uniform moisture laden cloudissues from the outlet end of said venturi chamber.

16. In combinatioin, an oxygen tent canopy, oxygen tent apparatus forcontrolled inhalation therapy in association with said canopy, meansincluding a cooling chamber external of the canopy for passing anoxygencontaining gas in heat exchange relationship with a coolingmedium, a liquid nebulizer at the outlet end of said means forentraining particles of finely divided liquid in said gaseous stream andpassing said moisture laden gas into said canopy to establish anatmosphere therein, means including a venturichamber in said nebulizerfor causing recirculation of themstablished atmosphere in said canopythrough said cooling phamber and said nebulizer wherein the recirculatedatmosphere is further cooled and saturated, and means for adjusting andmaintaining a predetermined temperature of the atmosphere Within saidcanopy.

References Cited in the file of this patent 7 UNITED STATES PATENTS2,778,617 Gibbon Jan. 22, 1957 2,785,768 Gauchard Mar. 19, 1957 FOREIGNPATENTS 405,564 Italy Aug. 20, 1943 973,081 France Sept. 6, 19501,047,652 France July 29, 1953

1. IN AN OXYGEN TENT APPARATUS FOR CONTROLLED INHALATION THEREAPY INASSOCIATION WITH A CANOPY, THE COMBINATION COMPRISING A HEAT INSULATEDCOOLING CHAMBER, A TUBULAR COIL WITHIN SAID CHAMBER FOR PASSAGE OF ANOXYGEN-CONTAINING GAS IN HEAT EXCHANGE RELATIONSHIP WITH A COOLINGMEDIUM, A LIQUID NEBULIZER ADAPTED TO ENTRAIN PARTICLES OF FINELYDIVIDED LIQUID IN SAID OXYGEN, A GAS NOZZLE FOR